Icon-based home certification, in-home leakage testing, and antenna matching pad

ABSTRACT

A method for determining the magnitude of leakage in a subscriber&#39;s premises CATV installation; a frequency multiplexer for coupling between an antenna and a receiver for the multiplexed frequencies; and, a method for a technician to certify a CATV subscriber&#39;s premises for the provision of CATV services are disclosed.

This application claims priority under 35 U.S.C. § 120 to U.S. patentapplication Ser. No. 15/595,876, filed May 15, 2017, which is acontinuation of U.S. patent application Ser. No. 14/435,628, now U.S.Pat. No. 9,667,956, which was filed Apr. 14, 2015 and was a nationalstage entry under 35 USC § 371(b) of International Application No.PCT/US2013/064993, filed Oct. 15, 2013, which claimed the benefit under35 U.S.C. § 119(e) of U.S. Ser. No. 61/713,707 filed Oct. 15, 2012, U.S.Ser. No. 61/807,046 filed Apr. 1, 2013, 61/823,966 filed May 16, 2013,and 61/862,716 filed Aug. 6, 2013. The entireties of those applicationsare expressly incorporated herein by reference.

Currently, in the CATV, (hereinafter sometimes cable), industry,technicians perform a series of tests at multiple points in a subscriberlocation before an installation is deemed “Quality” or “Clean.” Thisprocess is known as certification. It creates what is known as a “birthcertificate” for the subscriber premises. The management of amulti-system operator (hereinafter sometimes MSO) or smaller cablesystem operator identifies certain system performance limits that mustbe passed in order to certify the subscriber location as ready forconnection to the system. As an example, the operator's homecertification program might require the operator's installation andservice technicians to run tests at different points in the distributioncircuit at the subscriber's location (for example, home, apartmentbuilding, or place of business) in a certain order with certain limitson the test results at each point.

Another problem is with cable systems switching to digital. Leakage fromanalog cable channels is readily detected by systems, generally referredto as “taggers,” of the general types illustrated in, for example, U.S.Pat. Nos. 5,608,428; 6,018,358; 6,804,826, and references cited therein.The disclosures of these references are hereby incorporated herein byreference. This listing is not intended to be a representation that acomplete search of all relevant art has been made, or that no morepertinent art than that listed exists, or that the listed art ismaterial to patentability. Nor should any such representation beinferred.

However, distinct from an analog channel, a digital channel signal isspread fairly uniformly over 6 MHz. As a result, there is too little“tag” signal power in any sample, or “slice,” of the 6 MHz digitalsignal to reliably render the tag signal detectable.

A solution to this problem of tagging digital signals is to put a singlefrequency tag signal in the gap between adjacent 6 MHz digital channelsand then monitor the gap in an effort to detect the tag. If the tag isdetected, the operator has detected a leak. An enhancement putsmultiple, for example, two, tag signals in the gap at multiple, forexample, two, frequencies spaced far enough apart to discriminatebetween them. The operator looks for both/all of the inserted signals inorder to detect a leak. The use of multiple tag signals at multipledifferent frequencies is useful where, for example, systems areoverbuilt. Examples of these and similar techniques are described in,for example, PCT publication WO 2013/003301. Again, the disclosure ofthis reference is hereby incorporated herein by reference. This listingis not intended as a representation that a complete search of allrelevant art has been made, or that no more pertinent art than thatlisted exists, or that the listed art is material to patentability. Norshould any such representation be inferred.

SUMMARY

A method for determining the magnitude of leakage in a subscriber'spremises CATV installation comprises disconnecting the network at asuitable network port, coupling a frequency source to the port so that ahigh power offset is maintained, shielding the frequency source toprevent a signal level meter or leakage receiver from receiving radiatedfrequency source oscillations, transporting a signal level meter orleakage receiver around the premises, and logging signal levels measuredby the signal level meter or leakage receiver as the signal level meteror leakage receiver is transported.

Illustratively, the method further comprises addressing excessive signallevels thus logged.

Illustratively, disconnecting the network at a suitable network portcomprises disconnecting the network at the subscriber's premises groundblock.

Illustratively, coupling a frequency source to the port comprisescoupling a dual oscillator to the port.

Illustratively, coupling a coupling a frequency source to the port sothat a high power offset is maintained comprises coupling a dualoscillator to the port at a level in the range of about 40 dB to about70 dB above the level provided by the network.

Illustratively, logging signal levels measured by the signal level meteror leakage receiver as the signal level meter or leakage receiver istransported comprises calculating GT from the equation

P _(R) =P _(T) −L _(L) +G _(T) −L _(fs) +G _(R)

-   where P_(R)=received power in dBmV;-   P_(T)=transmitted power in dBmV;-   L_(L)=line loss in the port and the subscriber's premises's internal    cabling;-   G_(T)=gain in dBi of the transmitting antenna;-   L_(fs)=loss in dB attributable to the space between the leak and the    receiving antenna; and,-   G_(R)=gain in dBi of the receiving antenna.

Further illustratively, the method comprises analyzing the measurementto ascertain the location and extent of the leak.

Further illustratively, the method comprises generating a work order torepair the leak responsible for the calculated G_(T).

Further illustratively, the method comprises analyzing the measurementto ascertain the likelihood of interference from the premises enteringthe CATV system through the leak responsible for the calculated G_(T)and disrupting other CATV services.

Further illustratively, the method comprises analyzing the measurementto ascertain isolation between the CATV system and the premises.

Further illustratively, the method comprises providing the measurementto (a) server(s) operated by the CATV system operator, or to whoseservices the CATV system operator subscribes, and entering themeasurement into the subscriber's file, along with the time(s) themeasurement(s) was/were made, subscriber location/identity, andinformation about whether, and if so, when, a work order was filled.

Further illustratively, the method comprises entering the measurementinto a management information base and generating from the managementinformation base an alert concerning the status of one or morecomponents or functions of the CATV plant.

Further illustratively, the method comprises subtracting the poweroffset from the signal level, converting the result to a field strengthand displaying the resulting field strength on, for example, a displayassociated with the signal level meter or leakage receiver.

A frequency multiplexer is provided for coupling between an antenna anda receiver for the multiplexed frequencies. The multiplexer divides areceived frequency spectrum into at least a low band and a high band.The multiplexer includes a low pass filter for passing the low band fromthe antenna to the receiver and a high pass filter for passing the highband from the antenna to the receiver. The LPF and HPF are coupled inparallel between an output port of the antenna and an input port of thereceiver.

Illustratively, the LPF comprises first and second inductances coupledin series between the output port and the input port, and a firstcapacitance coupled between the junction of the first and secondinductances and the receiver ground. The HPF comprises second and thirdcapacitances coupled in series between the output port and the inputport and a third inductance coupled between the junction of the secondand third capacitances and the receiver ground.

Further illustratively, the multiplexer comprises an antenna impedancematching network coupled between the output port and the LPF.

A method for a technician to certify a CATV subscriber's premises forthe provision of CATV services comprises: (a) locating the CATV tap atthe subscriber's premises; (b) coupling a certification instrument tothe tap; (c) displaying on a display associated with the certificationinstrument a screen or image or picture or icon of a first test of thecertification process; (d) executing the first test of the certificationprocess, the display then advising the technician if the subscriber'spremises passes or fails the first test; (e) displaying on the display ascreen or image or picture or icon notifying the technician what testthe technician needs to perform next; (f) executing the next test, thedisplay then advising the technician if the subscriber's premises passesor fails the next test; (g) repeating steps (e) and (f) for as manyadditional tests as are necessary to complete the certification process;and, (h) transmitting certification testing results to a servermaintained for this purpose.

Further illustratively, the method comprises: before step (a) issuing acertification work order; and, after step (g) closing out thecertification work order.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by referring to the followingdetailed description and accompanying drawings which illustrate theinvention. In the drawings:

FIGS. 1-8 illustrate steps of a screen- or image- or picture- oricon-guided process to be followed by a technician to perform asubscriber's premises certification of a CATV system connection;

FIG. 9 illustrates a method and apparatus for performing a subscriber'spremises certification; and,

FIGS. 10-18 illustrate a component useful with other equipment forperforming a subscriber's premises certification, and plots ofperformance characteristics of the illustrated component.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In subscriber premises certifications, currently most operators issuecertification work orders, FIGS. 1, 2. The technician arrives at thepremises, certification of which is sought, locates the tap and executesthe “Tap” macro, FIGS. 3-5, of the screen- or image- or picture- oricon-guided process of the invention. Once this step is complete thescreen- or image- or picture- or icon-guided process advises thetechnician if the tap passes of fails, FIGS. 5-7. At this time, thescreen- or image- or picture- or icon-guided process also notifies thetechnician what test the technician needs to perform next. For example,the screen- or image- or picture- or icon-guided process may require thetechnician to move on to the cable drop and perform the “Drop” testmeasurements there, using the limits set for the “Drop.” Again, oncethis step is complete the screen- or image- or picture- or icon-guidedprocess advises the technician if the drop passes or fails. At thistime, the screen- or image- or picture- or icon-guided process alsonotifies the technician what test the technician needs to perform next.For example, the screen- or image- or picture- or icon-guided processmay require the technician to move inside the subscriber's premises tothe cable outlet(s) or customer premises equipment (CPE), and performthe autotest there, FIG. 7. Once these tests of the screen- or image- orpicture- or icon-guided process are performed, the results are gradedagainst the limits set for the outlet(s) or CPE. The technician thenmoves on to the final test at the ground block (hereinafter sometimesGB), FIG. 6. Once the GB test is complete and the installation meets allthe requirements, the technician is directed to close out the job andtransmit the completed test documentation up to the server for systemmanagement purposes, FIGS. 7-8.

There are currently basically two available types of leakage gear.So-called “truck-mounted” units are mounted in vehicles that are drivenalong the cable plant, generally by maintenance/service technicians tomonitor leakage along the cable. These systems are generally quitesophisticated and, as a result, expensive, costing in the range of $3000or more.

With reference to FIG. 9, the second type of leakage gear is the typegiven to technicians who come into subscribers' facilities 100 to hookup cable service and check connections initially. As a part of theirinstallation process, sometime during the installation process thetechnicians walk around the house 100 with usually a fairly simplesignal level meter (hereinafter sometimes SLM) 102 with an antenna 104designed to receive signals in the cable 106 bandwidth. The presence ofa signal in excess of a threshold is cause for further investigationthat the cable 106 installation in the subscribers' premises 100 mayhave a flaw that could result in egress of downstream-bound signal fromthe cable system or, perhaps equally as importantly, ingress of signalfrom the premises 100 into the cable system in the upstream-bound“return band.” The SLM 102/antenna 104 combination is rather lesssophisticated, and, as a result, rather less expensive, typicallycosting in the $300-$600 range. At this price point, technicians can beequipped with the SLM 102/antenna 104 combination to check subscribers'premises 100 for leaks during an installation.

In-premises leakage mitigation is very important to the successfuloperation of a cable system with modern, high speed cable services.In-premises is part of the system that is not under direct control ofthe cable operator. As a result, things can and will happen, such asemissions and ingress, that can have a direct effect on the cablequality of service. Further, there are many new products, such as cellphones and cell-equipped tablets, which populate the premises which aresources of ingress and which can thus disrupt or degrade the quality ofvideo or data.

The cable industry is always concerned about leakage from the cableplant. Up until a few years ago, the industry was mostly interested inthe aeronautical band (about 138 MHz). More recently, with the cellphone providers' introduction of 4G, the cable industry has also becomeconcerned with the LTE band (about 750 MHz). For example, the TrilithicSeeker™ D instrument has the capability to monitor both of these bandsusing a diplexer (one combined output, two frequency separated inputs).This diplexer has a low band input in the range of about 138 MHz and ahigh band input in the range of about 750 MHz. This permits a vehicle tohave two external antennas, one tuned to about 138 MHz and the othertuned to about 750 MHz, with their outputs combined through the diplexerand then input to an SLM in the truck.

However, when the technician takes his leakage measuring instrument fromthe truck's mobile mount, the instrument is disconnected from thediplexer and dual antennas. While a portable diplexer with two antennasis not out of the question, this combination including the SLM, diplexerand two antennas, will be somewhat awkward for the technician to walkaround with, and somewhat difficult to use. In any attempt to use onlyone antenna to receive both frequencies, the mismatched frequency willbe almost undetectable due to impedance mismatch loss and reflections.With reference to FIGS. 10-18, the illustrated antenna multiplexerpermits a single antenna tuned for one frequency to work well at bothfrequencies. This antenna multiplexing concept is readily adaptable tothree, four, or more, frequencies.

The illustrated antenna multiplexer has a single input and a singleoutput. The signal combining and matching networks are internal to themultiplexer. The different matching networks for each frequency ofinterest are combined in the multiplexer.

A monopole antenna matching pad (hereinafter sometimes MAMP, multiplexeror diplexer) 130 couples a monopole (rubber duck) antenna 104 forreceiving dual frequency leakage signal to a receiver meter or SLM 102.The MAMP 130 is connected to the antenna 104 at a BNC (female) port 132,and to the receiver meter or SLM 102 at a BNC/F (male) port 134. Theresonant frequency of the antenna 104 is in the range of the upperfrequency of interest, here about 750 MHz.

With reference to FIG. 10, the MAMP 130 includes a BNC (female)connector 132, a piece 136 of beryllium copper, an enclosure body 138, aBNC/F (male) connector 134 and a piece 140 of, for example, FR-4, PCBwith two pins 142, 144 that couple to the center conductors of the BNCand F connectors 132, 134, to form the center conductors of the BNC andF connectors 132, 134. Assembly of the MAMP 130 is illustrated in FIG.11. The illustrated MAMP 130 is a two port matched diplexer, in which ahigh pass filter comprising capacitors 146, 148 and inductor 150provides a high frequency path to the SLM (FIG. 10) 102, and a low passfilter comprising an inductor 152, an inductor 154 and a capacitor 156matched by an antenna impedance matching network comprising an inductor158 and an inductor 160 to provide a low frequency path to the SLM 102(FIG. 14). FIG. 13. illustrates the schematic of the MAMP 130 when theantenna 104 is receiving high (operating/resonant) frequency signal. Atthis frequency, the antenna's source impedance is about 50Ω. FIG. 14illustrates the frequency response of the MAMP in the region of theresonant frequency of the antenna 104. FIG. 15 illustrates the schematicof the MAMP 130 when the antenna 104 is receiving the low frequencysignal. At this frequency, the antenna's source impedance is about 3Ω inseries with an approximately 18 pF capacitance. FIG. 16 illustrates thefrequency response of the MAMP in the region of the low frequencysignal.

To make a reliable and inexpensive PCB assembly, the illustrated MAMP130 PCB layout incorporates five printed inductors 150, 152, 154, 158and 160 instead of coil inductors. As illustrated in FIG. 17, threeprinted inductors 158, 152, 154 of the LPF are on one side and a HPF146, 148, 150, LPF capacitor 162 and a printed matching inductor 160 areon the other side (FIG. 18).

Among the advantages of the illustrated MAMP 130 are: one antenna 104with MAMP 130 can receive multiple frequencies; the MAMP 130 provides 10to 15 dB higher antenna gain at low frequency; the MAMP 130 readilyconnects to the antenna 104 and the SLM 102 for leakage testing; MAMP130 adapts the antenna 104's BNC connector 132 to the SLM 102's Fconnector 134; the MAMP 130 structure takes advantage of existingconstruction techniques that provide; simple, easy assembly and reliableoperation; and, MAMP 130 PCB layout reduces cost; provides betterperformance and permits easier matching tuning.

The monopole antenna 104 is coupled via BNC connector 132 through seriesinductors 158, 152 and 154 and BNC/F connector 134 to the SLM 102.Inductor 160 is coupled between the common terminal of inductors 158 and152 and SLM 102 ground. Capacitor 156 is coupled between the commonterminal of inductors 152 and 154 and SLM 102 ground. The seriescombination of capacitor 146 and capacitor 148 is also coupled betweenthe BNC connector 132 and the BNC/F connector 134. An inductor 150 iscoupled between the common terminal of capacitors 146 and capacitor 148and SLM 102 ground. When the low frequency is being measured, anadditional capacitor is coupled between the antenna 104 and SLM 102ground. In the previously discussed embodiment, in which the lowfrequency is about 138 MHz and the high frequency is about 757.5 MHz,the various component values may be, for example: 158 is about 46 nH;160 is about 12.5 nH; 152 is about 40 nH; 154 is about 47 nH; L5 isabout 12 nH; 156 is about 18 pF; 146 is about 5.1 pF; 148 is about 5.1pF; and, the capacitor between the antenna and SLM ground is about 18pF±2%.

In an illustrative embodiment, two CW test carriers at two frequenciesare injected at the ground block with a defined relationship to thesystem levels at those frequencies. For example, if the normal operatingsystem levels are +0 dBmV at the ground block 106, the technicianconnects the test generator to this point at +40 dBmV at bothfrequencies, for example, about 138 MHz (for example, about 139.25 MHz)and about 750 MHz (for example, about 757.5 MHz). This establishes atest signal level-to-system level relationship of 40 dB. These testsignals propagate through the subscriber premises 100 in the same manneras the CATV signal, only at higher levels. Since these test levels aremuch higher, a very sensitive, and typically more expensive, SLM is notneeded to detect the leakage. The economical SLM 102 includes a “rubberduck” antenna 104 frequency matched to capture the leakage as the SLM102 is moved through the subscriber premises 100. The SLM 102 isprogrammed to automatically account for the antenna factor and the factthat the test signal is, for example, 40 dB above system level, and toconvert the thus-adjusted readings to microvolts per meter (μV/m) fordisplay on SLM 102.

One set of sensitivity tests with the system indicate leaks at about 138MHz have a sensitivity of 1 μV/m @ +40 dB and 0.10 μV/m @ +60 dB. Leaksat about 750 MHz have a sensitivity in the range of 4 μV/m @ +40 dB and0.40 μV/m at +60 dB. These sensitivity ranges permit technicians to findeven very small leaks which are capable of causing ingress or egress incable, active cable elements, passive cable elements and customerpremises devices (hereinafter sometimes CPD) units. Although thesesensitivities are high, they should be immune to most noise-generatedfalse readings as the elevated readings are generally well above ambientnoise levels. This data can be appended to the premises “health” orpremises certification test data for a subscriber installation anduploaded to a permanent record of that installation in system managementsoftware, such as Trilithic Viewpoint™ software. In instances where afull SLM 102 is not needed, a leakage receiver for “leakage-only”applications can be used.

Further considering ingress into a premises cable plant, shieldingdefects in premises wiring systems and customer premises equipment orcustomer-provided equipment (hereinafter both sometimes CPE) have thepotential to collect and intermingle terrestrial signals with thedesired transmissions in the coax. There is typically a high correlationbetween these points of ingress and points of egress in the coaxialsystem, since a shielding defect works equally well to permit leakageinto, or leakage from, the cable system. At typical digital signallevels in the Long Term Evolution (hereinafter sometimes LTE) band,leakage levels of 1 μV/m can indicate shielding defects that couldcapture signals from nearby LTE devices sufficient to createinterference ratios of less than 30 dB, causing potential tiling oftelevision displays or other interruption to the subscriber's services.Although not reflecting all variables, the illustrated system includesthe capacity to approximate the leakage antenna “gain” (loss) from thepremises cabling using the formula:

P _(R) =P _(T) −L _(L) +G _(T) −L _(fs) +G _(R)

-   where P_(T)=power of the injected CW carriers-   L_(L)=loss in the coax and splitters to the point of the leak from    the source-   G_(T)=gain of the leakage antenna model-   L_(fs)=free space attenuation from the leak to the instrument    measurement antenna-   G_(R)=gain of the instruments antenna in dBd-   L_(f)=generally, the antenna is connected directly to the instrument    (no loss), and-   P_(R)=received power

Solving for G_(T) yields

G _(T) =P _(R) −P _(T) +L _(L) +L _(fs) −G _(R)

Thus, by knowing the received power (that is, the measured leakagepower), the transmit power (that is, the +40 dB or +60 dB signalsupplied by the carrier generator at the ground block), loss up to thelocation of the leak (approximated by the loss through the subscriber'sinterior cabling and flat loss from the ground block to the leak), freespace attenuation (typically related to the distance from the leak tothe rubber duck receive antenna, and calculated within the instrument),and the gain of the receive antenna (specified), the approximate gain ofthe leak model in dBd can readily be calculated. Once the approximategain of the leak model has been calculated, estimate can be made of theeffect of various other fields known to be present in the subscriberpremises (for example, LTE fields) by applying these fields to theingress antenna model and predicting the ratio of the desired (systemcarrier) to the undesired (tower or cell phone sourced signals).Problems may arise at locations where a cell tower is close (LTEdownstream frequencies), or where a cellular device in the subscriberpremises must transmit at high levels to reach the cell (LTE upstreamfrequencies).

Input level to the subscriber's in-premises distribution network is inthe range of −5 dBmV. The cable is disconnected, for example, at theground block, and a signal generator capable of producing at least twofrequencies, for example, about 138 MHz and about 750 MHz at levels of,for example, about +40 dBmV (the default level) and about +60 dBmV, iscoupled to the subscriber's in-premises network, again, usually at theground block. Thus, the offset for the default +40 dBmV is +45 dB. Theoffset for +60 dBmV is +65 dB. In the subscriber network there may besome one or more sources of what is known as “flat” (that is,non-frequency dependent, non-distance dependent) loss, for example, (a)splitter(s), (a) tap(s) and so on. A four-way splitter might have a lossin the range of −7 dB. A tap might have a loss in the range of −3 dB. Inaddition, there is line loss for the length of coaxial cable between theground block and a flaw or “leak” in the cable. This loss typically isfrequency dependent and might be, for example, 6 dB/100 ft. (about 30.5m) for about 138 MHz and 10 dB/30.5 m for about 750 MHz. Thus, theamount of loss is related to how far the leak is along the cable fromthe port at which the signal generator is coupled (again, typically, theground block). Since the injected signal level amplitude is so high (+40dBmV or +60 dBmV in the illustration), the exact numbers for the variouslosses are not so important as rough numbers and knowing what circuitelement(s) is (are) between the injection port and the leak. Forexample, a technician might assume one four way splitter and no tapsbetween the injection port and the leak. The leak “antenna” might beassumed to be a dipole radiator having a gain Gl dBd, and the measuringinstrument's antenna may be a monopole having known characteristics, forexample, a gain Gi dB. The technician is instructed to walk thedistribution network through the subscriber premises at a distance ofsay 3 m from the wall.

According to an illustrative example, a technician disconnects the cable106 at the subscriber's premises 100's ground block 208, where the cable106 enters the premises 100 and is split in “tree and branch” topologyinto branches 210 running to different cable 106 outlets 212 within thepremises 100. The technician then connects a dual oscillator 214, 216 tothe ground block 208, and two signals, one in the aircraft band and onein the LTE band, are provided to the premises 100's internal cable 106wiring 218. Illustrative signals are an approximately 139.25 MHz CWsignal in the aircraft band and an approximately 750 MHz CW signal inthe LTE band. These signals are provided at high levels. For example, ifthe cable 106 signal is provided to the ground block 208 at −5 to 0dBmV, a not-atypical level, the dual oscillator 214, 216 provides 60dBmV signals at the selected frequencies to the ground block 208(so-called power offset is about +60 dB to about +65 dB). Of course, thedual oscillator 214, 216 must be well shielded to prevent the dualoscillator 214, 216 from radiating, and the SLM 102/antenna 104combination from receiving, the selected frequencies radiated throughthe air from the oscillator 214, 216.

The technician walks around the premises 100 with his SLM 102/antenna104 combination, which may be equipped with a GPS to track thetechnician's movements. The SLM 102/antenna 104 combination logs signallevels as the technician moves. Peaks in the leakage signal are readilyapparent on the SLM 102's output, which may be analog (a meter or gauge)or digital (a digital display). If excessive leakage is detected, it canbe traced from the log of readings and associated technician locationsto (a) particular point(s) in the premises 100's internal cable 218wiring, fittings to output devices, etc., and directly and immediatelyaddressed and repaired. Again, the equation governing this process is

P _(R) =P _(T) −L _(L) +G _(T) −L _(fs) +G _(R)

-   where P_(R)=received power (at the SLM 102/antenna 104) in dBmV;-   P_(T)=transmitted power (at the dual oscillator 214, 216) in dBmV;-   L_(L)=line loss in dB in the ground block 208 and the house 100's    internal cabling 218;-   G_(T)=gain in dBi of the transmitting antenna (the gain of the leak    in dBi);-   L_(fs)=loss in dB due to free space between the leak and the    receiving SLM 102/antenna 104; and,-   G_(R)=gain in dBi of the receiving antenna 104.-   P_(R), P_(T), L_(L), L_(fs) and G_(R) typically are known. Thus,    G_(T) can readily be calculated.

Analysis of SLM 102/antenna 104 measurement results permits, forexample, the technician or a program running on a remote server 220 towhich the collected data is provided to ascertain the location 222 andextent GT of the leak and generate a repair work order.

Analysis of the SLM 102/antenna 104 measurement also permits, forexample, a program running on a remote server 220 to which the collecteddata is provided to ascertain the likelihood of interference from thepremises 100 entering the cable 106 system through the leak 222 anddisrupting other cable 106 services. For example, if a leak 222 is large(G_(T) large) and the subscriber uses a cell phone 224 or like device inthe premises 100, such a program can predict with reasonable accuracythe likelihood of cell phone 224 interference with cable 106 signalsprovided to terminal equipment 226, such as televisions, computers andthe like, in the premises 100.

Analysis of the SLM 102/antenna 104 measurement can also provide areasonably accurate indication of isolation. For example, if theinjected signal at the ground block 208 is at +60 dBmV and a −40 dBmVsignal level is read at the SLM 102/antenna 104, the cable 106 providermay reasonably infer that 100 dB of isolation exists between the cable106 system and the premises 100 at the SLM 102/antenna 104-to-cable 218measurement distance, for example, about 10 feet (about 3 m).

The SLM 102/antenna 104 measurement can also be used for workforcemanagement and analysis. The measurement will be returned, for example,by DOCSIS, WiFi and/or like utilities to (a) server(s) 220 operated bythe cable 106 system operator, or to whose services the cable 106 systemoperator subscribes. Here, the measurement(s) will be entered into thesubscriber's file, along with the time(s) the measurement(s) was/weremade, subscriber location/identity, information about when a work orderwas filled, and so on.

Information thus collected can also be entered into a managementinformation base to provide alerts concerning the status of the variouscomponents of the cable 106 plant.

In an example, at a frequency of about 757.5 MHz, P_(R)=−40.00 dBmV;P_(T)=+60 dBmV; L_(L)=15 dB; L_(fs)=39.73 dB; and, G_(R)=2 dBi. Again,P_(R)=P_(T)−L_(L)+G_(T)−L_(fs)+G_(R). Thus, G_(T)=−47.27 dBi. If theactual reading at the SLM 102 is −40 dBmV (corresponding to 162.76926μV/m at the SLM 102), and the power offset is 65 dB, the adjustedreceived power is (−40-65) dBmV, or −105 dBmV corresponding to a“corrected” leakage of 0.09 μV/m.

On the interference side, if a cell phone 224 producing a field strengthof 1.8 V/m (about 40.87 dB at the SLM 102) is positioned about 3 m(about 10 ft.) from the leak 222 (the transmitting antenna),L_(fs)=39.73 dB (that is, the loss between the cell phone 224 and theleak 222 is 39.73 dB) and the leakage antenna gain, G_(T)=−47.27 dBi,the cell phone 224 signal has a strength at the leak of about −46.14dBmV. Since the system level is −5 dB, the interference ratio (−5dB-(−46.14 dB)) is about 41.14 dB.

The SLM 102 includes a gauge, dial or display for each of thefrequencies of interest, for example, about 139.25 MHz and about 750MHz. All of the above calculations for each frequency are performed byan arithmetic module in the SLM 102. The results are output to thegauge, dial or display for each frequency.

1. A system for determining the magnitude of leakage in a subscriber'spremises installation for a cable network that is configured to providea signal level in a range of −5 dBmV to 0 dBmV, the system comprising: asignal generator configured to be secured to a suitable network port ata subscriber's premises to wiredly connect the signal generator to cablewiring in the subscriber's premises, the signal generator including afrequency source operable to generate an output signal in a range of 40dBmV to 70 dBmV above the signal level provided by the cable network,the frequency source being shielded to prevent transmission of radiatedfrequency source oscillations, and a signal level meter operable to betransported around the subscriber's premises and measure signal levelsradiating from the subscriber's premises, the signal level meterincluding an output device configured to output the signal levelsmeasured by the signal level meter, wherein the signal generator isconfigured to supply the output signal through the suitable network portto the cable wiring at the subscriber's premises so that a high poweroffset is maintained when the signal generator is secured to thesuitable network port and wiredly connected to the cable wiring.
 2. Thesystem of claim 1, wherein the output device includes a displayconfigured to display the signal levels measured by the signal levelmeter.
 3. The system of claim 1, wherein the signal level meter isoperable to measure a peak in the signal levels corresponding to theoutput signal generated by the signal generator.
 4. The system of claim1, wherein the signal levels include a gain of a leak in thesubscriber's premises corresponding to the output signal generated bythe signal generator.
 5. The system of claim 4, wherein the gain of theleak is G_(T) and the signal level meter is configured to output anindication of G_(T) and calculate G_(T) from the equation:P _(R) =P _(T) −L _(L) +G _(T) −L _(fs) +G _(R) where P_(R)=receivedpower in dBmV; P_(T)=transmitted power in dBmV; L_(L)=line loss in thesuitable network port and the subscriber's premises' cable wiring;G_(T)=gain in dBi of the transmitting antenna; L_(fs)=loss in dBattributable to the space between the leak and the receiving antenna;and, G_(R)=gain in dBi of the receiving antenna.
 6. The system of claim1, wherein the signal level meter is configured to subtract the highpower offset from the signal level provided by the cable network,convert a result to field strength, and display a resulting fieldstrength on the signal level meter.
 7. The system of claim 1, whereinthe frequency source includes at least two oscillators.
 8. The system ofclaim 1, wherein the signal generator configured to be secured to aground block of the subscriber's premises.
 9. A system for determiningthe magnitude of leakage in a subscriber's premises installation for acable network that is configured to provide a signal level in a range of−5 dBmV to 0 dBmV, the system comprising: a signal generator configuredto be secured to a suitable network port at a subscriber's premises towiredly connect the signal generator to cable wiring in the subscriber'spremises, the signal generator including a frequency source operable togenerate an output signal in a range of 40 dBmV to 70 dBmV above thesignal level provided by the cable network, the frequency source beingshielded to prevent transmission of radiated frequency sourceoscillations, wherein the signal generator is configured to supply theoutput signal through the suitable network port to the cable wiring atthe subscriber's premises when the signal generator is secured to thesuitable network port and wiredly connected to the cable wiring.
 10. Thesystem of claim 9, further comprising a signal level meter operable tobe transported around the subscriber's premises and measure signallevels radiating from the subscriber's premises, the signal level meterincluding an output device configured to output the signal levelsmeasured by the signal level meter.
 11. The system of claim 10, whereinthe output device includes a display configured to display the signallevels measured by the signal level meter.
 12. The system of claim 11,wherein the signal level meter is operable to measure a peak in thesignal levels corresponding to the output signal generated by the signalgenerator and display the peak on the display.
 13. The system of claim12, wherein the signal levels include a gain of a leak in thesubscriber's premises corresponding to the output signal generated bythe signal generator.
 14. The system of claim 9, further comprising aleakage detector operable to be transported around the subscriber'spremises and measure signal levels radiating from the subscriber'spremises, the leakage detector including an output device configured tooutput the signal levels measured by the leakage detector.
 15. Thesystem of claim 14, wherein the output device includes a displayconfigured to display the signal levels measured by the leakagedetector.
 16. The system of claim 15, wherein the leakage detector isoperable to measure a peak in the signal levels corresponding to theoutput signal generated by the signal generator and display the peak onthe display.
 17. The system of claim 16, wherein the signal levelsinclude a gain of a leak in the subscriber's premises corresponding tothe output signal generated by the signal generator.
 18. A system fordetermining the magnitude of leakage in a subscriber's premisesinstallation for a cable network, the system comprising: a signalgenerator configured to be secured to a suitable network port to wiredlyconnect the signal generator to cable wiring at the subscriber'spremises, the signal generator including a frequency source operable togenerate an output signal in a range of 40 dB to 70 dB above a signallevel provided by the cable network, the frequency source being shieldedto prevent transmission of radiated frequency source oscillations, and asignal level meter operable to be transported around the subscriber'spremises and measure signal levels radiating from the subscriber'spremises, the signal level meter including an output device configuredto output the signal levels measured by the signal level meter, whereinthe signal generator is configured to supply the output signal throughthe suitable network port to the cable wiring so that a high poweroffset is maintained when the signal generator is secured to thesuitable network port and wiredly connected to the cable wiring.
 19. Thesystem of claim 18, wherein the output device includes a displayconfigured to display the signal levels measured by the signal levelmeter.
 20. A system for determining the magnitude of leakage in asubscriber's premises installation for a cable network, the systemcomprising: a signal generator configured to be secured to a suitablenetwork port to wiredly connect the signal generator to cable wiring inthe subscriber's premises, the signal generator including a frequencysource operable to generate an output signal in a range of 40 dB to 70dB above the signal level provided by the cable network, the frequencysource being shielded to prevent transmission of radiated frequencysource oscillations, wherein the signal generator is configured tosupply the output signal through the suitable network port to the cablewiring when the signal generator is secured to the suitable network portand wiredly connected to the cable wiring.